The Group Resource Allocation (GRA) method is a method for allocating resources to a plurality of users (i.e., terminals or mobile stations) belonging to one group in order to reduce overhead of control messages that a base station transmits to mobile stations. Using the GRA method, it is possible to reduce signaling overhead in a network since the base station can compress and transmit control information, which is to be provided to mobile stations, on a group by group basis when individually allocating resources to mobile stations.
The base station can use group control information for configuring and allocating resources to one or more mobile stations belonging to one group. Here, group control information may be referred to as an “Advanced MAP” or “A-MAP”. Multiple information elements are individually coded in the A-MAP associated with user specific control information of a single user or a user group. In the A-MAP, an ID of each mobile station (for example, an STID of a specific mobile station, a broadcast STID, and/or a multicast STID) is CRC-masked to be transmitted.
Since the A-MAP is individually encoded and masked with an STID, each mobile station performs blind decoding of a region in which the A-MAP is transmitted in order to check whether or not an A-MAP destined for the mobile station is present. Here, the mobile station can detect the A-MAP using an STID, a broadcast STID, and/or a multicast STID (for example, a group ID, a persistent ID, a sleep/idle mode ID, or an MBS ID).
The mobile station performs blind decoding based on a MAP size used in a corresponding system. Here, the base station and/or the mobile station may limit the size and type of the MAP to specific sizes and types in order to reduce the number of blind decodings. For example, the base station and/or the mobile station may limit the size of the A-MAP information element (IE) to three sizes such as 56 (or 64), 96, and 144 bits or to two sizes such as 56 (or 64) and 96.
Here, let us consider the case in which one Minimum A-MAP Logical Resource Unit (MLRU) includes 48 data subcarriers, two MLRUs include 96 data subcarriers, and the size of the A-MAP IE is determined to be 56 or 96. Here, the base station may transmit each A-MAP IE to the mobile station by mapping a 56-bit A-MAP IE to 1 MLRU and mapping a 96-bit A-MAP IE to 2 MLRUs using an encoding method used for a downlink control channel (for example, using a Tail-biting convolutional code method or a puncturing method).